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OPS435 Python Lab 5

74 bytes removed, 15:57, 11 February 2019
PART 1 - Handling Errors
</source>You should get an exception error similar to the following:<source>
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TypeError Traceback (most recent call last) Fiel "<ipython-input-3-1b929b80ca50stdin> ", line 1, in <module>()----> 1 print(TypeError: Can't convert '5int' + 10)object to str implicitly
TypeError: Can't convert 'int' object to str implicitly
</source><br>'''Question:''' According to the exception error message, what do you think caused the error?<br><br>
:#Click on the link '[https://docs.python.org/3/library/exceptions.html#concrete-exceptions https://docs.python.org/3/library/exceptions.html#concrete-exceptions.]' and scroll or search for '''TypeError'''. Take a few moments to determine what a ''TypeError'' exception error means.<br><br>You should have learned that the TypeError exception error indicates a mismatch of a type (i.e. string, int, float, list, etc). If Python doesn't know how to handle it, perhaps we could change the number into a string or change the string into a number or at least provide a more user-friendly error message.<br><br>If we don't want the user of our program to have to learn how to read Python exceptions (which is a very good idea), we can catch/trap/handle this error when it happens. This is done with a specific block of code called a [https://docs.python.org/3/tutorial/errors.html#handling-exceptions '''try clause'''] where you place code in-between the '''try:''' and the '''except:''' coding blocks. In a general sense, it works like a modified if-else statement, where the try statement acts as a test, and the except statement will or will not handle the exception depending if it occurs or does NOT occur. That is to say, If no error occurs in the code contained in the '''except''' section, the script will continue as usual but if an error occurs in the except section, then it can be handled with additional coding (like an user-friendly error message).<br>Let's demonstrate to handle our TypeError error with code that first does not contain an error and then similar code that DOES generate an error.<br><br>
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